po: update Dutch translation
po: update Japanese translation
po: update German translation
po: update French translation
po: initial Hebrew translation
LanguageGlue: support Hebrew
Pages: remove obsolete function PossiblePageLayout()

.. and all of its backend code.  Has been superseded by the new
PagesConfigPanel.
Pages: remove local PageSettings copy

Use CommonInterface::GetUISettings() instead.
Pages: use PageLayout::IsDefined()
PageSettings: add functions FullScreen(), Aux()
PageSettings: split top_layout into two boolean flags

The code gets simpler by splitting the enum into the two flags "page
valid" and "infoboxed enabled".  The profile loader/saver gets some
migration glue code.  The profile format is unmodified, may be changed
later.